Some immigrants have avoided purchasing infant formula and food for their children through a federal nutrition program out of concern the Trump administration may block them from obtaining legal status, Politico reported Monday.

The news outlet reported that documented and undocumented immigrants have called local health providers asking to be taken off of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), a federal nutrition program that assists pregnant women and young children.

The individuals are reportedly alarmed that the Trump administration may punish immigrants who rely on public benefits, like the WIC program, Politico reported.

Agencies in at least 18 states have reported 20 percent drops in enrollment in WIC, Politico reported. The report, however, notes that not all of the decrease is a direct result of concerns over the Trump administration’s policies.

The improved economy and lower birth rate could also contribute to the lower enrollment numbers.

A spokesperson told Politico that the Department of Agriculture, which oversees the WIC program, is studying why eligible families are not enrolling or are discontinuing their participation in WIC.

The White House did not respond to requests for comment from Politico.

President Trump has made cracking down on immigration a hallmark of his administration.

He has regularly derided the U.S. as having the “worst” laws of anywhere in the world and called on Congress to pass legislation more strongly restricting illegal immigration, and reforming and limiting legal immigration programs.